Double Time - This gives you 2 initial charges to use with each used charge taking 20 seconds to tick over. However you have to wait a minimum of 12 seconds between each charge for you to be able to gain your rage. While this does offer great gap closing oppurtunity it does have its fall backs. If you used this twice in a row at first you must then wait around 18 seconds to use it again, and then if you used it everytime on cooldown thats a 20 second wait for every charge, which is just standard. Remember a full charge must be generated before the next one starts to regenerate. If you aim to use this talent to spam 2 charges in quick succesion everytime then to get this double charge affect you have to wait 40 seconds everytime for both charges to be ready at once. Finaly if you want to ensure you get your rage everytime it takes a little bit more management, which can be tricky with the distractions of battle.

Warbringer - Standard 20 second cooldown on charge but with the addition of a 3 second stun (up from 1.5) and a built in snare giving you more time to land a few attacks. This seems mainly built for PvP, and is a very viable choice and can often be a game changing mechanic, however this still has its fall backs. 20 seconds is still a fairly long cooldown even if you do get a more useful charge, (most other escapes or gap closers are around 15 seconds standard or glyphed/talented) also mages/displacer beast druids can still blink out of this leaving you a 20 seconds wait. From a pve perspective it can be useful for tanks to stun that dangerous mob or whatever but from a dps side you can also disrupt a tanks group pull , neither affect appliable to bosses.

So there you go, while the other 2 do have great uses they also have a few fall backs or more management. So if you want a straight up, shortish cooldown, gap closing, rage making bull rush to your foes then don't overlook this talent guys its better than it looks, and hey, it does its job right ? :D